Remove/install heater unit

AR83.70-P-5302GD

Remove/install heater unit

08.03.2019

Model

168.### 1# with engine 668.940/941/942

with heater booster or retrofitted Thermo Top C stationary preheating

3

Coolant outlet line, heater

10

Coupling, control lines

A6

Heater unit

4

Coolant feed line, heater

11

Holder (heater booster)

M13/2

Coolant recirculation pump

6

Nut

12

Combustion air intake line

X73/2

Coolant circulation pump connector

7

Fuel feed line

14

Exhaust line

Y23

Fuel metering pump

9

Coupling, power supply

a

Rubber mount

Y23x1

Fuel metering pump connector

6a

Screw

17

Screw

M13/2

Coolant recirculation pump

11

Holder (heater booster)

a

Rubber mount

X73/2

Coolant circulation pump connector

13

Bow

A6

Heater unit

Y23

Fuel metering pump



Remove

 Danger

Risk of explosion caused by fuel vapors igniting, risk of poisoning caused by inhaling combustible gases and risk of injury caused by burns during and after operation of heater unit

Do not operate stationary heater, auxiliary heater or engine with heater booster in closed rooms or when refueling. Allow heater unit to cool down after operation and wear protective gloves.

AS83.70-Z-0002-01A

Distinguishing features stationary heater/stationary preheater/heater booster

AH83.70-P-0003-01B

1

Remove/install bottom sections of soundproofing

AR94.30-P-5300GD

 Warning

Risk of injury to skin and eyes suffering scalding from contact with hot coolantspray. Risk of poisoning from swallowing coolant.

Do not open cooling system unless coolant temperature is below 90 °C. Open cap slowly and release the pressure. Do not pour coolant into beverage containers.
Wear protective gloves, protective clothing and safety glasses.

AS20.00-Z-0001-01A

2

Release pressure in coolant circuit

 To do so, unscrew cap of coolant expansion reservoir slowly by 1/2 turn.

3

Clamp off coolant outlet line (4) and coolant feed line (3)

 Clamp

*000589543700

4

Disconnect coolant hoses (3) from heater (A6) and coolant circulation pump (M13/2)

 Collect escaping coolant in a clean vessel and, after installation of heater, pour back into coolant expansion reservoir

 Installation: Inspect condition of collar clamps, replace if necessary.

 Danger

Risk of explosion caused by fuel igniting, risk of poisoning caused by inhaling and swallowing fuel as well as risk of injury to eyes and skin caused by contactwith fuel.

No fires, sparks, open flames or smoking. Pour fuels into suitable and appropriately marked containers only.
Wear protective clothing when handling fuel.

AS47.00-Z-0001-01A

5

Clamp off fuel feed line (7) and disconnect from fuel metering pump (Y23)

 Installation:
Replace clamp
on fuel feed line.

 Clamp

*000589403700

6

Disconnect circulation pump connector (X73/2) and fuel pump connector (Y23x1)

 Installation: Replace cable tie.

7

Disconnect connection couplings (9, 10) from heater (A6)

8

Release nut (6) from holder (11)

 Detach heater (A6) from stud bolt.

9

Pull exhaust gas line (14) through partition

10

Slide heater (A6) with holder (11) in direction of travel until rubber mounts (a) are pushed out of crossmember, and guide out heater (A6) in downward direction

 

Disassemble/assemble

11

Disconnect exhaust gas line (14) from heater (A6)

12

Disconnect fuel line (7) from heater (A6)

13

Disconnect heater holder (11) with fuel pump (Y23) from heater (A6)

 Holder (11) is secured using 3 screws (6a).

 Bolt, bracket to heater

*BA83.70-P-1009-01A

14

Remove circulation pump connector (X73/2) from holder (11)

 Rotate connector on holder (11) and detach.

15

Disconnect circulation pump (M13/2) from heater (A6)

 Assembly: Hook bracket (17) into heater (A6) first.

16

Install in the reverse order

Check

17

Check relay assignment of heater (A6) on right in engine compartment



GF54.15-P-1257-02B

18

Check fuse assignment of heater (A6) on right in engine compartment



GF54.15-P-1256-02A

19

Bleed coolant circuit after installation of heater

AR83.70-P-5302-01D

20

Check cooling system for leaktightness

AR20.00-P-1010GF

21

Perform heater booster (HB) diagnostic function check



AD83.70-P-3004A



AZ83.70-P-5302-08B

 If the heater (A6) switches off automatically before reaching its operating temperature and cannot then be restarted,

there is a fault interlock (continue with).



Override malfunction interlock

AR83.70-P-5302-07B

 Stationary heater

Number

Designation

MODEL 129, 163, 168 with Thermo Top C heater

BA83.70-P-1009-01A

Bolt, bracket to heater

Nm

10